the alternative to get two USB harddrives to do a on-site copy of the complete server to portable storage is basically off the table, since it would need Falk to move to IPHH and sit there and wait for the disks to get copied

If I remember correctly thet have a service where you can upload basically unlimited data to backup, and it only costs something to dowwnloaad that back when you need it.. (and even that was not too expensive)

but I'm not willing to continue taking care about that on my own risk and expense, hoping for somebody maybe contributing via donations to a deprecated private paypal account that never really been meant to get used for that stuff

ok then, from my point of view the only differences would be in legal things ( cannot read German so no opinion ) and isolating the board election to a small group - a risk but should be better in the long run as you want the board to be "steady"